U.S. Department of the Interior

U.S. Geological Survey

Cadmium Recycling in the United States in 2000 

By Jozef Plachy 

U.S. GEOLOGICAL SURVEY CIRCULAR 1196–O

FLOW STUDIES FOR RECYCLING METAL COMMODITIES IN THE UNITED STATES 
U.S. DEPARTMENT OF THE INTERIOR 

GALE A. NORTON, Secretary 

U.S. GEOLOGICAL SURVEY

CHARLES G. GROAT, Director 

U.S. GEOLOGICAL SURVEY, RESTON, VIRGINIA : 2003 

Version 1.0 

Published online in the Eastern Region, Reston, Va., 2003. 

Manuscript approved for publication July 28, 2003. 

Any use of trade, product, or firm names in this publication is for 

descriptive purposes only and does not imply endorsement by 

the U.S. Government. 
FOREWORD


As world population increases and the world economy expands, so does the demand 

for natural resources. An accurate assessment of the Nation’s mineral resources must 

include not only the resources available in the ground but also those that become available 

through recycling. Supplying this information to decisionmakers is an essential part of the 

USGS commitment to providing the science that society needs to meet natural resource 

and environmental challenges. 

The U.S. Geological Survey is authorized by Congress to collect, analyze, and 

disseminate data on the domestic and international supply of and demand for minerals 

essential to the U.S. economy and national security. This information on mineral 

occurrence, production, use, and recycling helps policymakers manage resources 

wisely. 

USGS Circular 1196, “Flow Studies for Recycling Metal Commodities in the 

United States,” presents the results of flow studies for recycling 26 metal commodities, 

from aluminum to zinc. These metals are a key component of the U.S. economy. 

Overall, recycling accounts for more than half of the U.S. metal supply by weight 

and roughly 40 percent by value. 

Charles G. Groat 

Director 

III 
CONTENTS


Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III


Conversion Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V


Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . O1


Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1


Global Geologic Occurrence of Cadmium . . . . . . . . . . . . . . . . . . . . . . . . . . . 1


Primary Production and Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3


Sources of Secondary Cadmium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Old Scrap Generated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3


New Scrap Generated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4


Disposition of Cadmium Scrap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Old Scrap Recycling Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Infrastructure of Cadmium Scrap Recycling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5


Processing of Cadmium Scrap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6


Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7


References Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Appendix—Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

FIGURES 

1. 	Diagram showing U.S. cadmium materials flow in 2000 . . . . . . . . . . . . . . . . . . . . O2

2. 	Graph showing U.S. cadmium consumption, by end-use pattern, from 1980

through 2000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . O5


TABLE 

1. Salient statistics for U.S. cadmium scrap in 2000 . . . . . . . . . . . . . . . . . . . . . . . . . .O3

IV 
CONTENTS V 

CONVERSION FACTORS 

Multiply By To obtain 

Mass 

metric ton (t, 1,000 kg) 1.102 short ton (2,000 pounds) 

For temperature conversions from degrees Celsius (°C) to degrees Fahrenheit (°F), use the following: 

°F = (1.8 × °C) + 32 
FLOW STUDIES FOR RECYCLING METAL COMMODITIES IN THE UNITED STATES 

Cadmium Recycling in the United States in 2000 

By Jozef Plachy 

ABSTRACT 

Recycling of cadmium is a young and growing industry 

that has been influenced by environmental concerns and 

regulatory constraints. Domestic recycling of cadmium 

began in 1989 as a byproduct of processing of spent nickelcadmium batteries. In 1995, International Metals Reclamation Co. Inc. expanded its operations by building a dedicated cadmium recycling plant. In 2000, an estimated 13 percent of cadmium consumption in the United States was 

sourced from recycled cadmium, which is derived mainly 

from old scrap or, to lesser degree, new scrap. The easiest 

forms of old scrap to recycle are small spent nickel-cadmium batteries followed by flue dust generated during recycling of galvanized steel and small amounts of alloys that 

contain cadmium. Most of new scrap is generated during 

manufacturing processes, such as nickel-cadmium battery 

production. All other uses of cadmium are in low concentrations and, therefore, difficult to recycle. Consequently, 

much of this cadmium is dissipated and lost. The amount of 

cadmium in scrap that was unrecovered in 2000 was estimated to be 2,030 metric tons, and an estimated 285 tons 

was recovered. Recycling efficiency was estimated to be 

about 15 percent. 

INTRODUCTION 

The purpose of this report is to show trends in consumption and recycling1 of cadmium in the United States 

during 2000. The amount of cadmium that is recycled, 

however, is difficult to estimate for a number of reasons. 

Because the production data by International Metals Reclamation Co. Inc. (INMETCO), which is the only cadmium 

recycler in the United States, is confidential, important 

information for this study is not available; INMETCO is 

located in Ellwood City, Pa. An additional reason is that the 

recovered cadmium from baghouse dust, which is generated by primary metal smelters, is processed during zinc 

refining and is usually included in the production statistics 

for primary cadmium metal. The main impediment to a 

study of cadmium recycling is that data on the amount of 

spent nickel-cadmium (NiCd) batteries in the marketplace 

are not readily available. 

1Definitions for select words are found in the Appendix. 

Cadmium is a soft, silver to bluish-white metal that is 

produced mainly as a byproduct from the mining, smelting, 

and refining of other nonferrous metals, mainly zinc. About 

75 percent of cadmium is used for batteries followed by pigments (12 percent), coatings and plating (8 percent), and stabilizers for plastics and similar synthetic materials (4 percent). Because cadmium is a byproduct of other metals, its 

price is not subject to ordinary supply-and-demand dynamics. If zinc production increases, then cadmium supply will 

also increase, regardless of cadmium market demands. During the past few years, cadmium supply has generally 

exceeded cadmium demand, owing to overall growth in the 

zinc market and to tightening of regulatory controls. This 

imbalance has driven cadmium prices to such a low level that 

for many zinc smelters disposing of raw cadmium is more 

financially expeditious than refining it. For cadmium recyclers, most of the profit is in the fees collected from suppliers, not in the price of produced cadmium. 

GLOBAL GEOLOGIC OCCURRENCE 

OF CADMIUM 

Cadmium is a naturally occurring metallic element that 

is present in trace amounts of between 0.001 and 25,000 parts 

per million and less than 1 microgram per liter in the Earth’s 

crust and oceans, respectively. Greenockite (CdS), which is 

the most common cadmium mineral, does not form its own 

deposits, but is usually associated with sphalerite (ZnS), 

which is the most common zinc ore mineral. About 80 percent of cadmium output worldwide is estimated to be a 

byproduct of primary zinc production. The average ratio 

between contained zinc and cadmium in sphalerite is about 

250 to 1. The remaining 20 percent of cadmium is obtained 

from secondary sources, such as baghouse dust, recycled cadmium products, and the production of other primary metals, 

mainly lead and copper (Morrow, 2001, p. 1). The cadmium 

in lead and copper ores is associated with the zinc sulfide 

present rather than with the other minerals (Wedow, 1973). 

The temperature of formation of zinc deposits has a partial bearing on cadmium concentration. In general, contact 

metamorphic and irregular replacement deposits that formed 

at relatively high temperatures have less cadmium content 

than intermediate hydrothermal ores and sedimentary 

deposits. 

 01 
02 FLOW STUDIES FOR RECYCLING METAL COMMODITIES IN THE UNITED STATES 

Figure 1. U.S. cadmium materials flow in 2000. Values are in metric tons of contained cadmium. 
CADMIUM RECYCLING IN THE UNITED STATES IN 2000 03

Table 1. Salient statistics for U.S. cadmium scrap in 2000. 

[Values in metric tons of contained cadmium unless otherwise specified]

Old scrap: 

Generated1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2,400** 

Consumed2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285**

Consumption value3 . . . . . . . . . . . . . . . $100.5 thousand**

Recycling efficiency4 . . . . . . . . . . . . . . . . . . . . 15 percent*

Supply5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2,400** 

Unrecovered6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.,030**

New scrap consumed7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5** 

New-to-old-scrap ratio8 . . . . . . . . . . . . . . . . . . . . . . . . . . .2:98**

Recycling rate9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 percent**

U.S. net exports of scrap10 . . . . . . . . . . . . . . . . . . . . . . . . . . .85** 

Value of U.S. net exports of scrap3 . . . . . . . . . . . .$30 thousand**

1Cadmium content of products theoretically becoming obsolete in the 

United States in 2000. 

2Cadmium content of products that were recycled in 2000. 3Value of cadmium scrap based on primary cadmium metal price.

4(Old scrap consumed plus old scrap exported) divided by (old scrap 

generated plus old scrap imported plus any old scrap stock decrease or 

minus any old scrap stock increase). Some items were not available. 

5Old scrap generated plus old scrap imported (not available) plus old 

scrap stock decrease (not available). 

6Old scrap supply minus old scrap consumed minus old scrap exported (not available) minus old scrap stock increase (not available). 

7Includes new (prompt) industrial scrap but excludes home scrap. 

8Ratio of quantities consumed, in percent*(See Appendix—Definitions).

9Fraction of the metal apparent supply that is scrap on an annual basis. 

It is defined as (consumption of old scrap plus consumption of new scrap) 

divided by apparent supply (see appendix), measured in weight and 

expressed as a percentage. 

10 Trade in scrap is assumed to be principally in old scrap. Net exports 

are exports of old scrap minus imports of old scrap (not available). 

Cadmium-containing zinc deposits occur in many 

diverse geological environments. Contact metamorphic, or 

skarn, deposits are deposits contained in metamorphosed 

sedimentary rocks, often limestone, that have been altered 

and enriched by zinc- and cadmium-bearing solutions from 

adjacent igneous intrusives. These deposits are usually low 

in cadmium, and U.S. deposits of this type are not important 

zinc or cadmium sources. 

Another type of deposit, which is an evolution of the 

contact-metamorphic deposit, is the irregular replacement 

deposit. In these deposits, which tend to be higher in cadmium content, ore solutions migrate considerable distances 

from the igneous source. These zinc- and cadmium-bearing 

solutions seek out weaknesses in the surrounding rock and 

form irregularly shaped replacement deposits. 

Vein-type deposits occur as tabular masses that fill 

faults and joints in the host rock. Generally, these deposits 

have planar walls. As zinc- and cadmium-bearing solutions 

move away from the point of origin, they deposit metals as 

a result of local temperature and pressure conditions.

Hence, cadmium may be enriched greatly in certain parts of 

the deposit and depleted considerably in other parts. 

Strata-bound-type zinc deposits are the most important 

commercially. In platform carbonates, they occur as thin 

zones of replacement mineralization or breccia fillings. 

These are the classic Mississippi Valley-type deposits, 

which may cover several hundred square kilometers

(Wedow and others, 1973). Metamorphic equivalents of 

such deposits generally have mineralization in lenticular 

masses and are generally lower in cadmium. Stratiform 

deposits involve mineralization that forms lenticular masses 

at the contacts of metamorphosed sedimentary and interbedded volcanic rocks. Cadmium concentrations in these

deposits are low to intermediate (Plunkert, 1985). 

PRIMARY PRODUCTION AND PROCESSES 

By the end of 2000, only Pasminco Zinc, Inc., was producing primary cadmium at its zinc smelter in Clarksville,

Tenn. Big River Zinc Corp., Sauget, IL, ceased production

of cadmium in 2000 owing to low prices and the loss of a 

major consumer, a NiCd battery manufacturer. Big River

found it more economically expedient to dispose of raw cadmium in the slag than to process it. Both primary cadmium

producers used an electrolytic process and recovered cadmium as a byproduct during the roasting and leaching of zinc

concentrate. After removal of various impurities, cadmium

is electrowon to a 99.99-percent or more purity and cast into

50-millimeter (mm)-diameter balls or 250-mm-long sticks

or is oxidized to produce cadmium oxide powder. 

SOURCES OF SECONDARY CADMIUM 

OLD SCRAP GENERATED 

Because data are not available on trade in NiCd batteries, and imported batteries are the major source of old scrap 

generated, estimating old scrap generated is difficult. Based 

on the author’s calculations of the amount of cadmium 

recovered and Informinc (undated) estimates of cadmium 

discarded in 2000 in household batteries and appliances, 

old-scrap generated is estimated to be 2,400 metric tons. 

During the past 30 years, cadmium applications have 

shifted steadily away from coatings, which accounted for

about 50% of consumption in the 1960s, to NiCd batteries,

which accounted for about 75 percent of consumption in

2000 (Plachy, 2001). Consequently, spent batteries are the

major source of recycled cadmium, and the recycling rate

for these batteries varies according to battery size. About 80

percent of large industrial batteries in the world, which contain about 20 percent of all cadmium used in batteries, is

estimated to be recycled, but only about 20 percent of small

consumer NiCd cells and batteries are recycled (Hugh Morrow, President, International Cadmium Association, oral

commun., 2002). The calculated recycling rate for cadmium

in the United States was 13 percent in 1998. Figure 1 shows

*Correction posted on June 29, 2009.

**Corrections posted on August 25, 2010.
04 FLOW STUDIES FOR RECYCLING METAL COMMODITIES IN THE UNITED STATES 

the estimated quantity of old scrap generated, and the flow 

of this metal through processing and use. Table 1 lists salient 

statistics derived from figures shown in this flow chart. 

Two major categories of batteries are recycled—wet 

cell and dry cell. Most wet cell batteries are lead-acid batteries primarily used in motor vehicles. Dry cell batteries, 

which are also known as consumer batteries, are either primary or rechargeable. About 80 percent of rechargeable batteries are made of nickel and cadmium. In 2000, an estimated 3.5 billion consumer batteries were sold in the United 

States, of which almost 10 percent were NiCd batteries 

(Informinc, undated). The market for rechargeable batteries 

is growing faster than the market for nonrechargeable (primary) batteries mainly owning to increased sales of portable 

and cordless products. About 80 percent of all rechargeable 

batteries are not sold separately, but instead are inclosed in 

consumer products; these products require a broad range of 

power requirements—from low-power drain (for example, 

portable computers) to high-power drain (for example, 

power tools). For low-power-drain applications, nearly all 

NiCd batteries have been replaced by batteries that use new 

technologies, such as nickel-metal hydride (NiMH) and 

lithium-ion (Li-ion) batteries. For high-power-drain applications, nearly all batteries are NiCd. 

Quantities of other sources of secondary cadmium, 

such as electric arc furnace dust (flue dust), electroplating 

wastes, filter cakes, and sludges, are small and diminishing 

because of low cadmium prices. The amount of these other 

sources was not available for this study. 

Figure 2 shows how the share of various end uses of 

cadmium has changed since 1980. Batteries have a much 

larger share, and coatings and plating, a much smaller share. 

NEW SCRAP GENERATED 

Almost all new scrap is generated at the plants that use 

cadmium, mainly battery manufacturing plants, and is recycled inhouse or through tolling arrangements with recyclers. 

Small amounts of new scrap are probably generated at pigment-manufacturing facilities, electroplating shops, alloy 

manufacturers, and plastic-stabilizer production facilities. 

The amount of cadmium produced from new scrap was estimated to be 5 t in 2000. 

DISPOSITION OF CADMIUM SCRAP 

All consumer batteries take up an estimated 1 percent of 

Municipal Solid Waste (MSW) but contribute a disproportionately high percentage of certain toxic metals, mainly 

mercury and cadmium, to the waste stream. Mercury has 

been used as a gas-suppressing additive in the batteries, and 

its use is being eliminated by changes in the internal design 

of batteries. Cadmium, however, is used as an electrode and, 

therefore, is the basic power source of the battery. Any 

reduction of cadmium would cause a proportionate reduction 

in the energy output. Consequently, reduction of cadmium in 

MSW could only be achieved by increased recycling or 

replacement of NiCd batteries with less toxic alternates. 

About 2,030 t of cadmium in household batteries is in appliances and was discarded and unrecovered in 2000 

(Informinc, undated). 

Because a high percentage of NiCd batteries are being 

discarded, cadmium can accumulate at the MSW disposal 

site and could slowly leach into ground and surface waters 

from these landfills. To lessen or even eliminate the likelihood of environmental contamination, public pressure 

forced local and Federal Governments to regulate disposal of 

toxic materials and to encourage recycling of those that are 

reusable. This has been the main motivating force in the creation of numerous cadmium recycling programs. Because 

small spent batteries are a major source of cadmium contamination when incinerated or disposed of in landfills, most 

of the collection and recycling programs were aimed at these 

batteries. The first Federal effort at regulation of all hazardous wastes was the Resource Conservation and Recovery 

Act of 1976. This regulation provided an exemption for residential use; different regulations applied to identical 

scrapped batteries depending on who had used them. The 

Universal Waste Rule of 1995 unified the treatment of all 

hazardous waste, regardless of the origin. Under the rule, the 

assumption that NiCd batteries are nonhazardous until they 

reached the recycling facility was especially beneficial for 

battery recycling. Individual States, however, were allowed 

to accept or reject the new rule. Those States that did not 

adopt the rule continued to consider NiCd batteries to be 

hazardous material and required special safeguards for transportation through those States. The different requirements by 

individual States made interstate transportation of collected 

NiCd batteries to the recycler too expensive. As a result, collection of recyclable batteries suffered despite the adoption 

of the Universal Waste Rule by 32 States by 1996. This 

obstacle was eliminated with the passage of the Mercury 

Containing and Rechargeable Battery Management Act (also 

called the Battery Act), which was signed into law on May 

13, 1996. The Battery Act has two purposes—the phasing 

out of mercury in batteries and the efficient and cost-effective collection, transportation, recycling, and/or proper disposal of used NiCd batteries, used small sealed lead-acid 

batteries, and certain other regulated batteries. The Battery 

Act also established national uniform labeling requirements 

for regulated batteries and rechargeable consumer products 

and easy removability of batteries in these products that were 

manufactured domestically or imported and sold in the United States. Because the Battery Act is mandatory for all 

States, national organizations for the collection of spent 

NiCd batteries and guaranteed unhindered transportation of 

these batteries throughout the United States could be established. These two aspects became the needed impetus for the 

addition of a cadmium recycling facility at the stainless steel 

(Fe-Ni-Cr) recycling works of INMETCO and the rapid 

growth of Rechargeable Battery Recycling Corp. (RBRC). 
CADMIUM RECYCLING IN THE UNITED STATES IN 2000 05

Figure 2. U.S. cadmium consumption by end-use pattern, from 1980 through 2000.

OLD SCRAP RECYCLING EFFICIENCY 

Although trade in batteries is significant, data are not 

available, particularly for NiCd batteries. Because trade is 

an important factor in estimating old scrap generated and, 

therefore, old scrap recycling efficiency, making an estimate 

of old scrap recycling efficiency is difficult. On the basis of 

the study in Informinc (undated) and estimates of 2,032 t of 

cadmium discarded in 2000, a 15-percent recycling efficiency was calculated. This is thought to be an optimistic 

evaluation. With improved collection systems, however, this 

percentage could be raised significantly. 

INFRASTRUCTURE OF CADMIUM 

SCRAP RECYCLING 

Because large quantities of small batteries are discarded 

by a large number of individual consumers, most collection 

efforts are aimed at improving the recycling rate of these 

batteries. This, however, is proving to be the most difficult 

aspect of recycling because changing the attitudes and habits 

of the public is not easy. To make recycling as convenient as 

possible, several collection programs have been developed 

to meet the needs of battery manufacturers and the numerous consumers, firms, organizations, and agencies that use 

such diverse products as power tools, cordless phones, and 

personal computers. 

Kinsbursky Brothers Inc. and RBRC are the two largest 

organizations that collect spent NiCd batteries. Kinsbursky 

Brothers is a California-based environmental management 

company that specializes in integrated waste management 

and resource recovery programs and services. The company 

was founded in the 1950s and gradually expanded to new 

areas, which included recycling lead acid and all nonlead 

acid battery chemistries, auto and petrochemical catalysts, 

and precious-metal refining. Kinsbursky Brothers latest 

expansion, in collaboration with RBRC, was into NiCd battery collection (Kinsbursky Brothers, Inc., undated). 

A financially independent nonprofit organization, 

RBRC generates revenues for the recycling program by 

licensing its seal of approval to individual companies 

involved in the manufacture, import, and distribution of 

rechargeable batteries or battery-operated products. The 

collection program, which is called Charge Up to Recycle!, 

contains several key elements, such as uniform battery 

labeling, removability from appliances, national network of 

collection systems, regulatory relief to facilitate battery collection, and widespread publicity to encourage public participation, that are required by Federal and various State 

laws. To deal with batteries generated by many different 

sources, RBRC has set up separate collection systems for 

business and public agencies, communities, licensees, and 

retailers. Batteries from these collection systems are transported to two consolidation points located in Minnesota and 

New Jersey. All batteries from these consolidation points are 

shipped to INMETCO by the United Parcel Service (UPS) 

or by national common carriers. In 2000, RBRC and Kinsbursky Brothers collected 1,770 t of batteries (Norm England, Director, Portable Rechargeable Battery Association, 

oral commun., 2001). Most of the NiCd batteries collected 

by Kinsbursky Brothers in the 13 Western States were sent 

to a processing facility in France, and batteries collected by 

RBRC in the remaining States were sent to INMETCO. 

In 1995, INMETCO began reclaiming cadmium from 

spent batteries at its newly built cadmium recycling plant and 

currently (2000) produces about 290 t of cadmium metal per 

year (Cassidy, 2001). The $5 million High Temperature 
06 FLOW STUDIES FOR RECYCLING METAL COMMODITIES IN THE UNITED STATES 

Metal Recovery plant addition, which was built by Davy 

International Ltd., was the first facility of its kind in the 

world. It is capable of processing more than 3,500 metric 

tons per year (t/yr) of spent NiCd batteries. During the past 

few years, the amount of industrial batteries that was recycled has remained constant, but recycling of small consumer 

batteries increased and now composes about 60% of all batteries recycled. To supplement RBRC’s collection programs, 

INMETCO developed its own collection programs because a 

larger recycling operation lowers the unit cost of the secondary metal production. INMETCO’S programs also meet the 

varied needs of battery manufacturers and the numerous 

agencies, consumers, firms, and organizations that use the 

many diverse products that contain NiCd batteries. The most 

successful collection program is the prepaid container program in which companies that generate spent batteries purchase a 14-kilogram container for collection and shipment of 

spent batteries. The fee for the container includes shipping 

by UPS, handling, sorting, and processing. Additional collection programs include mail-back envelopes, a small package program, and so-called “milk runs.” The mail-back program is used by companies that want to provide their individual customers with the means to recycle their batteries 

without using a consolidation location. The company sends 

their customers a prepaid envelope addressed to INMETCO 

when a new battery is purchased; there is no direct cost to the 

customer. The small package program is intended for small 

businesses that are not part of the RBRC program; the transportation cost for this program is the responsibility of the 

generator. The milk runs are used by generators that are too 

far from INMETCO and are willing to share transportation 

expenses. In this program, one transporter travels to several 

sites, usually in conjunction with other trucking business, to 

pick up several drums of spent batteries. Because industrial 

users of NiCd batteries are prohibited from discarding the 

batteries in municipal waste dumps, they are recycled 

through collection programs in which producers of these batteries collect and send their spent batteries to INMETCO 

(Money, Tomaszewski, and Bleakney, undated). 

PROCESSING OF CADMIUM SCRAP 

The processes of cadmium recovery from industrial 

and consumer sealed NiCd batteries differ only in the manner of battery preparation. Industrial batteries, which contain an average of 9 percent cadmium (up to 25 percent 

Cd), are drained of potassium hydroxide electrolyte, the 

battery tops are cut off, and the nickel and cadmium plates 

are manually separated. The cadmium plates are washed, 

dried, and sent to a cadmium recovery facility. Nickel 

plates, metal cases, and retort residues are smelted into 

remelt alloy pig for the stainless steel industry; they are not 

refined by INMETCO, but are sold directly to the stainless 

steel industry for making new stainless steel. Small sealed 

batteries that contain as much as 17 percent cadmium must 

be hand sorted because only newer batteries are color 

coded, and very few of them carry bar codes, which makes 

optical scanning and other automated sorting very difficult. 

At the request of recycling organizations, INMETCO collects not only NiCd batteries, but also other batteries, such 

as Ni-MH, Li-ion, and lead acid. Alkaline batteries that are 

inadvertently included in the shipment to INMETCO are 

disposed of in a landfill. All these batteries are manually 

sorted by three people, and NiCd batteries are then transported by conveyor belt to a 330-kilogram-per-hour (kg/h) 

crusher. About 20 percent of the total weight of small consumer batteries is plastic, which is reduced to about 7 percent by using magnetic separation of crushed batteries. The 

remaining plastic cover is burned off at the thermal oxidizer at a temperature of about 300° C When the temperature 

inside the oxidizer drops to about 200° C, because of a new 

charge, additional burners are engaged. 

Since the installment of three original batch-type thermal oxidizer retort vessels at INMETCO in 1995, the supply of collected spent batteries soon outpaced the processing capacity, and a fourth retort furnace was added a year 

later. Soon this new addition proved to be inadequate. As 

battery recycling expanded, bottlenecks that had developed 

in the recycling flow had to be eliminated; during the past 3 

years, improvements have cost about $3.3 million. First, a 

continuous-flow rotary thermal oxidizer that is capable of 

processing about 250 kg/h of NiCd batteries with virtually 

no operator involvement (there is only one operator for all 

oxidizers) was installed. Second, the capacity of the new 

rotary oxidizer was increased to more than 500 kg/h with 

the subsequent addition of a mechanical plastic removal 

mill. Third, three new retort furnaces dedicated entirely to 

portable NiCd battery recycling were added. And, last, the 

small battery receiving and sorting area was enlarged and 

improved, and the ventilation of welding fumes at the cadmium recovery equipment repair shop where retort furnaces 

and crucibles are repaired/welded was improved. 

The washed and dried cadmium plates from industrial 

batteries and the crushed small batteries from which most 

of the plastic casing has been removed are charged into a 

cadmium recovery furnace called a crucible. The charge is 

augmented with carbon, which is added as a reductant. The 

furnace is heated to a temperature higher than the melting 

point of cadmium (321° C) but below the melting temperature of nickel (1,453° C). For a more-even heat in the oven, 

the crucible is equipped with burners at the bottom and in 

the middle. Melted cadmium is continuously collected in a 

water bath. The final products, which are called Cadmet 

shots, are small flattened discs, 4 to 6 mm in diameter, 

which facilitate handling and reduce erratic rolling. They 

have a purity of greater than 99.95 percent cadmium, some 

as high as 99.999 percent cadmium. As the final step, Cadmet shots are drummed, weighed, and assayed. Cadmets of 

at least 99.95 percent cadmium are shipped to NiCd battery 
CADMIUM RECYCLING IN THE UNITED STATES IN 2000 07

manufacturers for reuse in new batteries. Lower purity 

(between 99.75 and 99.95 percent) Cadmets are used in the 

manufacture of corrosion-resistant coatings and cadmiumcontaining stabilizers, alloys, and/or pigments. 

INMETCO processes other batteries but only to the 

degree that is possible with equipment that is already available. For example, NiMH batteries are shredded and melted at the company’s rotary hearth furnace or submerged 

electric arc furnace (EAF) to produce an alloy. The rareearth components from NiMH batteries are added to the 

nonhazardous slag, which is sold as a replacement for limestone used for roadbeds and construction fillers. Nickeliron, nickel metal hydride, lithium ion, and mercury-free 

zinc carbon (also known as carbonaire) batteries are also 

shredded and then added to a rotary hearth or submerged 

EAF where most of the zinc is reduced and then fumed off 

into the waste-gas stream. The fume particulate is collected 

and sent offsite as a crude zinc oxide for zinc and lead 

recovery. The remaining zinc, manganese, and other metal 

portions are fed to an EAF where final zinc volatization 

takes place. The metal casing is smelted, and the bulk of the 

manganese is incorporated into the metal product. The carbon is used as a reductant, which is a replacement for coke, 

during cadmium distillation. Lithium ion and lithium polymer batteries are processed to recover cobalt, copper, and 

lithium. The metal casings are added to the EAF for smelting into a metal ingot that consists of iron (64 percent), 

chromium (14 percent), nickel (13 percent), and other elements. Lead acid and mercury batteries are not processed 

at INMETCO, but are sent to appropriate secondary lead 

and mercury producers (Mark Tomaszewski, International 

Metals Reclamation Co. Inc., oral commun., 2002). 

In addition to the pyrometallurgical process in which 

cadmium vapor is collected and then solidified by condensation or oxidation, hydrometallurgical cadmium recycling 

processes are used. In these wet chemical processes, batteries are dissolved in strong acids and then subjected to 

selective precipitation or ion exchange reactions to separate 

cadmium compounds from nickel and iron compounds. 

OUTLOOK 

Statistics indicate that worldwide sales of rechargeable 

NiCd batteries have been declining by about 1 to 2 percent 

per year since 1993. This decline is mostly caused by the 

loss of certain market segments to other batteries, such as 

NiMH or Li-ion. NiCd batteries, however, are expected to 

maintain a good share of the market because they are 

renowned for their long life and minimum maintenance 

requirements, high power density, wide temperature operating range, good charge retention, and reasonable price. For 

many applications, such as cordless power tools and emergency lighting, no better alternative is currently (2000) 

available. At the same time as the sale of NiCd batteries 

declined, recycling rates have been increasing at an average 

rate of more than 6 percent per year since 1995 (Money and 

Griffin, 2000, p. B75). Both these trends bode well for the 

environment. 

Recyclers are counting on increased recycling in the 

United States, and not only of NiCd batteries, but also of 

alkaline and Li-ion batteries. In 2001, Toxco Inc. (a subsidiary of Kinsbursky Brothers) acquired Moltech Corp.’s 

patented cadmium recovery facility and equipment for 

recycling NiCd batteries. Because about 80 percent of all 

batteries are alkaline, Toxco is also planning to recycle 

alkaline batteries at its Trail, British Columbia, Canada, 

facility. By using established technology, Toxco will be 

able to reintroduce the recycled materials into the manufacture of downstream metals. Ozark Fluorine Specialties 

(a division of Toxco in Tulsa, Okla.) is to produce lithium 

salts and electrolytes used in the manufacture of lithium 

batteries and ultra capacitors from recycled Li-ion batteries. With these new initiatives, Kinsbursky Brothers 

appears to be positioning itself as the foremost primary 

and rechargeable battery recycler (Kinsbursky Brothers, 

Inc., undated). These new initiatives in themselves, however, will not increase battery recycling. Their success 

will be determined by the extent to which the battery 

manufacturing industry is able increase the collection rate 

of spent batteries. This may turn out to be the biggest hurdle to overcome. 

The rate of recycling could probably be improved by 

raising the awareness about the advantages of recycling as 

opposed to disposal of spent batteries or offering some type 

of other incentives. Increased recycling would reduce seepage of hazardous constituents from landfills and reduce 

harmful airborne components that are released during the 

incineration of waste. Recycling would also help to sustain 

our natural resources, not only by recycling the material 

content of batteries, but also by saving the energy used for 

processing of these materials. For example, INMETCO’s 

recycling process is about 50-percent more energy efficient 

and more environmentally beneficial than metal production 

from virgin ore (Money and Griffin, 2000, p. B76). Less 

fuel consumption means less air pollution—an additional 

environmental benefit. Increases in the recycling rate 

would likely require a variety of efforts, such as an expensive multimedia advertisement campaign, Federal Government-mandated pealable stickers on products to remind 

consumers to recycle spent batteries, and so forth. At current (2000) prices for revenue-generating materials recovered from the spent batteries, especially nickel, and the 

realized benefit for the environment from less cadmium 

pollution, the expense that would be required to significantly increase the recycling rate may not be cost effective. 

Therefore, only a gradual increase in recycling rate can be 

expected in the near future. 
08 FLOW STUDIES FOR RECYCLING METAL COMMODITIES IN THE UNITED STATES 

REFERENCES CITED Money, Ken, Tomaszewski, Mark., and Bleakney, Russell, 

Cassidy, D.J., 2001, U.S. plants operated solely to recycle 

metal-rich wastes, in Recycling metals from industrial 

waste, Addendum—A three-day short course and 

workshop with emphasis on plant practice: Golden, 

Colo., June 19–21, presentation, unpaginated. 

Informinc, [undated], Industry program to collect nickelcadmium (Ni-Cd) batteries, accessed May 2002 at URL 

http://www.informinc.org/battery.html. 

Kinsbursky Brothers, Inc., [undated], Who we are, accessed 

May 2002 at URL http://kinsbursky.com/aboutus.html. 

Morow, Hugh, 2001, Cadmium, executive commodity 

reports: London, Mining Journal Books Ltd., 32 p. 

Money, Ken, and Griffin, Kathleen, 2000, Economic considerations on the feasibility of battery recycling: Ellwood City, Pa., International Metals Reclamation Co. 

Inc., p. B72-B81. 

[undated], Pyrometallurgical battery reclamation at the 

International Metals Reclamation Company: Ellwood 

City, Pa., International Metals Reclamation Co. Inc., 

16 p. 

Plachy, Jozef, 2001, Cadmium: U.S. Geological Survey 

Mineral Commodity Summaries 2001, p. 38-39. 

Plunkert, Patricia, 1985, Cadmium, in Mineral facts and 

problems, U.S. Bureau of Mines Bulletin 675, p. 

111–119. 

Wedow, Helmuth, Jr., 1973, Cadmium, in Brobst, D.A., and 

Pratt, W.P., eds., United States mineral resources: U.S. 

Geological Survey Professional Paper 820, p. 105–109. 

Wedow, Helmuth, Jr., Kiilsgaard, T.H., Heyl, A.V., and Hall, 

R. B., 1973, Zinc, in Brobst, D.A., and Pratt, W.P., eds., 

United States mineral resources: U.S. Geological Survey 

Professional Paper 820, p. 697–711. 
CADMIUM RECYCLING IN THE UNITED STATES IN 2000 09

APPENDIX—DEFINITIONS


apparent consumption. Primary plus secondary production (old scrap) plus imports minus exports plus 

adjustments for Government and industry stock 

changes. 

apparent supply. Apparent consumption plus consumption 

of new scrap. 

dissipative use. A use in which the metal is dispersed or 

scattered, such as paints or fertilizers, making it exceptionally difficult and costly to recycle. 

downgraded scrap. Scrap intended for use in making a 

metal product of lower value than the metal product 

from which the scrap was derived. 

home scrap. Scrap generated as process scrap and consumed in the same plant where generated. 

new scrap. Scrap produced during the manufacture of metals 

and articles for both intermediate and ultimate consumption, including all defective finished or semifinished articles that must be reworked. Examples of new scrap are 

borings, castings, clippings, drosses, skims, and turnings. 

New scrap includes scrap generated at facilities that consume old scrap. Included as new scrap is prompt industrial scrap—scrap obtained from a facility separate from 

the recycling refiner, smelter, or processor. Excluded 

from new scrap is home scrap that is generated as 

process scrap and used in the same plant. 

new-to-old-scrap ratio. New scrap consumption compared 

with old scrap consumption, measured in weight and 

expressed in percent of new plus old scrap consumed 

(for example, 40:60). 

old scrap. Scrap including (but not limited to) metal articles that have been discarded after serving a useful 

purpose. Typical examples of old scrap are electrical 

wiring, lead-acid batteries, silver from photographic 

materials, metals from shredded cars and appliances, 

used aluminum beverage cans, spent catalysts, and tool 

bits. This is also referred to as postconsumer scrap and 

may originate from industry or the general public. 

Expended or obsolete materials used dissipatively, 

such as paints and fertilizers, are not included. 

old scrap generated. Metal content of products theoretically becoming obsolete in the United States in the 

year of consideration, excluding dissipative uses. 

old scrap recycling efficiency. Amount of old scrap recovered and reused relative to the amount available to be 

recovered and reused. Defined as (consumption of old 

scrap (COS) plus exports of old scrap (OSE)) divided 

by (old scrap generated (OSG) plus imports of old 

scrap (OSI) plus a decrease in old scrap stocks (OSS) 

or minus an increase in old scrap stocks), measured in 

weight and expressed as a percentage: 

COS + OSE ×100 

OSG + OSI + decrease in OSS or − increase in OSS 

old scrap supply. Old scrap generated plus old scrap 

imported plus old scrap stock decrease. 

old scrap unrecovered. Old scrap supply minus old scrap 

consumed minus old scrap exported minus old scrap 

stock increase. 

primary metal commodity. Metal commodity produced or 

coproduced from metallic ore. 

recycling. Reclamation of a metal in usable form from scrap 

or waste. This includes recovery as the refined metal or 

as alloys, mixtures, or compounds that are useful. 

Examples of reclamation are recovery of alloying metals (or other base metals) in steel, recovery of antimony in battery lead, recovery of copper in copper sulfate, 

and even the recovery of a metal where it is not desired 

but can be tolerated—such as tin from tinplate scrap 

that is incorporated in small quantities (and accepted) 

in some steels, only because the cost of removing it 

from tinplate scrap is too high and (or) tin stripping 

plants are too few. In all cases, what is consumed is the 

recoverable metal content of scrap. 

recycling rate. Fraction of the apparent metal supply that 

is scrap on an annual basis. It is defined as (consumption of old scrap (COS) plus consumption of new 

scrap (CNS)) divided by apparent supply (AS), measured in weight and expressed as a percentage: 

COS + CNS × 100 

AS 

scrap consumption. Scrap added to the production flow of 

a metal or metal product. 

secondary metal commodity. Metal commodity derived 

from or contained in scrap.